Chocolate cysts, also known as ovarian endometriomas, are a manifestation of endometriosis. Generally, it refers to the implantation of endometrial tissue on the ovaries, causing local infiltration and invasion, leading to cysts. Because the fluid inside the cyst resembles chocolate, they are called chocolate cysts. Chocolate cysts may cause infertility, for the following reasons: First, chocolate cysts can affect the function of the ovaries, causing ovulatory disorders and ovarian dysfunction. The secretion of estrogen and progesterone is relatively low, and these factors can lead to infertility. Second, chocolate cysts can cause adhesions within the pelvic cavity, affecting the egg-picking function of the fallopian tubes. This factor can also lead to female infertility.